Section navigation

[boxadesign]

Use this place to discuss the section navigation component in the ONS Design System

[jrbarnes9]

Fixed in #1612

[jrbarnes9]

Allow group headings in section navigation.

Currently, to produce the following lefthand navigation menu, the section navigation component has to be used mutiple times for each sub-headed group. This results in multiple nav elements for what is essentially a single navigation menu.

Allowing multiple lists within the component, with sub-headings, will simplify and improve the labelling of the nav landmarks on the page.

Note:
We're already handling these groups/sections in this way in the sub-navigation macro for the header component

[jrbarnes9]

Raised #2621